GL1200 Frame Cut / Modification

GL1200 Frame Cut / Modification

I knew I didn’t want to keep the “fake tank” of the Goldwing. To me, aside from the engine, the tank is probably one of the largest focal points of a bike. I ended up cutting out the framework that held the fake tank and welded in a center spine so a Harley tank could be installed.

The neck of the frame was cut and rotated out to increase the rake. The pics of the process aren’t with me right now. I will dig ’em up and post them when I get around to it.

You’ve INCREASED the rake angle? Jeebuz. Well now I’ve got a sick feeling in my stomach that you’re building a CHOPPER out of this ‘Wing…. Ugh.

Have you not seen the ENDURANCE RACER developments of the GL1000, from the ’76 Bol D’Or the “DLF-1000” Or the Rickman/Dresda chassis with the ’72-’73 prototype former side-car engine ‘Wing? These guys ran against the SOHC-4 999cc VX1000 Japauto – AND – the DOHC Honda RCB & RS1000 prototype racers, throughout the FIM Bol D’Or & Isle of Man Tourist-Trophy “TT” etc etc.

Which is to say they could TURN A CORNER! Ha-ha. They showed the true potential of the ‘WING, long before it was messed with by the likes of Craig F’n Vetter. Turned into a rolling barcalounger/lazyboy etc. It had once been the biggest fastest bike in the Honda line-up. Soon to be eclipsed by the likes of the CB1100R etc, but for it’s era it was THE go-to Honda SUPERBIKE! IMHO the Doncque “DLF-1000” etc show an alternative direction for a best rebuild of the biggest version of the four-banger ‘Wing – and the aforementioned CB1100R should show you the way forward with respect to the 41mm TRAC fork etc. Especially when we’re talking about the GL1200 with the vented 296mm front rotors – Though if you’ve got the spiral center 276mm discs, the aformentioned RCB/RS1000 Endurance Racers could point out a way forward with THOSE as well – ‘Cause there’s a guy on eBay who’s doing CAST-IRON replacement discs for the SOHC-4 CB750’s (& there’s a 5-bolt version of THAT rotor, found on the ’77-’78 CB750A Hondamatic!) who has agreed in principle to building a version of these discs which would fit the spiral pattern GL1200 rotors – also found on the CB1100F & CX650T turbo – If these rotors were built up to 296mm spec they’d make for some of the most awesome period-correct brakes for a contemporary Honda – Meanwhile, the WHEELS themselves could have some interesting prospects. Number one for a “DLF-1000” style rebuild, there’s a guy who did a CB900C wire-spoke Chopper, goes by the handle “6pkrunner” over on the CB750C.com CUSTOM forum – And remembering the CB900C has the same rear hub & ‘pumpkin’ as the GL1100 – And remembering the GL1100 rear end is a cross-compatible part to the GL1200 itself! He took the hub & spun it down to a plug, then welded it into a hollowed-out CB750K DRUM hub – I’ve dubbed this the “Weld-Up HUB method” – There’s also the bolt-up flange plates, which add more weight, but would be a decent way to mod the FRONT hub – There was also a very rare Unobtainium, Canadian only one-year-only, POLICE model only, CB750P7 front hub, which was a FIVE-bolt version of the CB750K/GL1000 DUAL-disc front hub – (Not to be confused with the DOHC-4 CB750K single-disc version!) With that one, you could have any & all of these possible GL1200 & RCB/RS1000 & CB1100R-C/D etc front rotors. As well as the single-piece “dished” 5/10-spoke discs in 276mm, OR their 296mm counterpart found only on the ’81 CB1100RB – which is now being made in replica form, from “Metalgear AU” in Australia. They’re the most light-weight of the type, surely not up to the job on a GL1200 – But they’d kick but on the ’78 twin-shock CBX six-cylinder, or the DOHC-4 CB750K and/or CB750A Hondamatic, or CB750FZ ’79 model with the silver COMSTAR wheels – I’d prefer a wider lighter 2.50×18″ COMSTAR front wheel, rebuilt with the Akront “NERVI” rim – there’s one on the Moto-Morini “Excalibur” front wheel, interchangeable with the Comstar – If only we could find one in 3.50×18″ or 4.25×18″ for that matter! Ah, but there ARE specimens in 3.00×16″ & 3.50×16″ so a CB750C Custom or CB900C ten-speed, the GL1100 & GL1200 for that matter, COULD have some widened lightened (50% the mass in equivalent sizes!) “NERVI” rim type wheel-set. Either which way – the early type SILVER full-Aluminum (’79 vintage) COMSTAR rims, with an 18″ up front, paired to those dished 296mm rotors? WOW – That’s an awesome light-weight racing wheel. I suppose the Cast-Iron CB1100F/GL1200 276mm embiggened to 296mm would be the NEXT most light-weight (& the most effective with the Cast-Iron coefficient of friction, far superior to the stock stainless-steel type) Then the CB750A Hondamatic 9-rivet 5-bolt and/or CB750K 296mm version of GL1000 276mm discs, (6- bolt for wire-spoke, 5-bolt for Comstar) would be slightly heavier than that – And then the heaviest & yet the most surface area & cooling capacity paired to the best heat-sink factor etc, would be the CB1100R-C/D CBX pro-link & GL1100 etc VENTED 296mm rotors, & their analogue with the solid silver center-carrier from the GL1200 – which I expect to be the best type to run on an Endurance Racer on the “short-track” type of race where you’re up against a lot of turns etc. TONS of options there – And for the wheel-set, one might build the Comstar wheels to 2.75×18″ using a CBX ’81-’82 “Pro-Link” rear wheel, and use the GL1100’s longer swing-arm & ‘pumpkin’ etc, it MIGHT be able to squeeze that fat 18″ rear wheel into the swing-arm. I suppose there’s also a 4.00×17″ rim in the same type & brand, oddly enough on a reverse-spoke WIRE wheel, from the Yamaha dual-sport/adventure-bike “Super Tenere” 1100cc or 1200cc whichever it was – If bolted up to the Comstar hub, it MIGHT squeeze into that GL1100 swing-arm. And with the 4.00″ width one MIGHT get into a 160/60-17 spec rear tire. For perhaps an even weirder version of the “weld-up HUB” method, one might utilize the BOOMERANG COMSTAR wheels, converted to a shaft-drive type. Though of course the CX650T & CX500T also had Gold Boomerang shaft-drive type rear hub. And THAT might be rebuilt using the 3.00×18″ rim from CB900F2 or CB1100R – or a 3.50×17″ from VF1000F-II – All of these might give the big ‘WING a real boost in terms of unique ’80s Honda go-fast aesthetics. Personally, I LOVE the Comstar wheels. But I’ve settled for building WIRE-SPOKE wheels, ’cause of the adaptability inherent to mixing & matching hubs & rims – I’d do the same with the COMSTAR rims if I could only find the correct sizes of “NERVI” rims, which the Morad company let slide into endangered-species status when they took over the reins of the AKRONT company.

Between over-sized rotors & a fat 41mm TRAC anti-dive fork, some juicy Comstar or wire-spoke wheels – these are the hallmarks of ’80s Honda RACING motorcycles – All it needs then would be a stripped down light-weight BUBBLE style fairing – Something from the BMW aftermarket line-up could emulate the “DLF-1000” quite nicely –

And THEN perhaps, some reasonable changes to the geometry. Ergonomics for starters, some rear-set pegs & low clubman handlebars or some low adjustable clip-on bars – ideally taken from the concurrent V-four Honda VF1000R, they’d fit the GL1200 fork PERFECTLY – There are some alternative fork yokes / ‘triple-trees’ from CBR & VFR series, the VF1000R type would probably bolt straight up to the GL1200 steering stem. You’d want the “sport-kit” throttle housing, best found from CBX550F stocks, so the cables don’t catch on the gas-tank.

One notable change which the “DLF’ did, is very clearly shown via the victorious BMW boxer-twin R90S AMA Superbike from the inaugural ’76 race at Daytona, Steve McLaughlin IIRC – They tipped the front of the engine up by putting the engine mounts above the lower frame rail, with the rear mount below it – this had the effect of tilting the crank-shaft up in front, raising the “jugs” allowing greater cornering clearance, effectively tipping the steering stem (DOWN, which is where you SHOULD tip it!) and/or pointing the swing-arm down in the rear – Which would require longer rear shocks. If you just added the shocks, this would place undue forces on the universal joint, wearing it out prematurely and losing TORQUE in so doing – The ride height & “sag” needs to be set up such that the universal-joint is straight for the most of it’s operation, which is to say pointing slightly downwards so that one’s weight straightens it out while riding – This is the same reason (well ONE good reason) which shorter rear shocks are a bad idea for the CRUISER types who would turn the ‘Wing into a CHOPPER – Of course the addition of a taller rear WHEEL would help to jack up the engine as it is. Yet we don’t want to tip the front end down ’cause the jugs would drag in the corners. You could well imagine all of the additional ground-clearance which could be gained – for which reason, you’d want to swap out the SEAT for a very low flat racing style seat, just a fiberglass pan directly over the frame rails, and a dense memory-foam pad, neoprene even. That way your toes could still reach the ground.

This would of course raise the CENTER OF GRAVITY – I would think the “DLF-1000” put it’s gas tank up over the engine due to the mono-shock rear end. Nevertheless it would be a mistake to do so if you don’t HAVE to – With the twin-shock version of an “Endurance ‘Wing” or “Racing ‘Wing”, it would probably be best to keep the gas-tank right where it is. Or perhaps to add some ADDITIONAL fuel capacity via an extra tank over the frame’s spine section. Then the battery & electrics/electronics etc could all be stuffed up into the front of the FAIRING – maybe a removable panel around the headlight section might allow work on the wiring etc without having to remove the bodywork? As for the shape, well – the CB1100R gas-tank is iconic for ’80s Honda racing. I’d let you take a mould or scan off of my polished ‘toaster-tank’ on my “CB900K0 Bol Bomber”, perhaps it could be used to make a fiberglass faux-tank ‘skin’ for the “GL1200R” or “DLF-1200” – a simple cheap aluminum rectangle could be stuffed underneath that lightweight cover, to max out tank volume & thereby the range between fill-ups. Of course the CX650T Turbo bodywork would also make a great template for this new RACING ‘WING…..

Which would blow the likes of RANDAKK’S “RC-001” out of the water. Surely he’d then be able to help with a super-charger & twin down-draft carburetors? Mmmmmm. Though for actual AHRMA “Forgotten-Era” and or Bol D’Or Classics, etc – there wouldn’t be any TURBO or SUPER-CHARGER allowed. They’d even put restrictions on carburetor throat diameter, for having more than 954cc’s 1025cc’s or thereabouts. I’m not sure how they’d look at a four-barrel monoblock carburetor. The ‘Wing itself might be uniquiely poised for an advantageous fueling loop-hole, maybe even enough to get past it’s shaft-drive. And just like How Ducati & Moto-Guzzi utilized the twin vs four-cylinder displacement handicap, the GL1200 might come to dominate Classic Endurance racing.

Though personally, I’d bet money on the VF1100S Sabre and/or / VF1100C Magna, if somebody would simply throw together a Magni MV Agusta or Yamaha XS-Eleven style “outrigger-bearing” type SHAFT-TO-CHAIN CONVERSION kit – I suppose they did it with some of the late ’80s GUZZI racers, but I can’t see this being done with the ‘Wing. For the V-four Honda though, it’s simply correcting a disadvantage which had been needlessly foisted upon the Magna & Sabre. We could see the Sabre set up as an RS850R or FW1000RS “Water-Whale” replica, while the Magna steals the show as an ‘homage’ to the ’60s Czechoslovakian Grand-Prix racer the CZ TYPE 860 – Especially with a wire-spoke wheel-swap! Potential there for some truly GORGEOUS ‘Retro-Fried’ projects, not to mention serious power! RC-Engineering’s Russ Collins did some long-stroke crank-shaft kits for the VF in the early ’80s. Add that to a big-bore job, and you’re probably talking upwards of 1250cc’s-1300cc’s! Plus a WOLF exhaust which was also offered for the series, as well as the shaft-to-chain conversion so the Torque & Rear Wheel Horse-Power isn’t being ROBBED by the shaft-drive. WOW, what a huge potential therein….

At the same time, the GL1200 ain’t such a shabby contender. IMHO they’d BOTH enrich the diversity of Classic Endurance and/or Superbike racing. I’d want to see ’em race against EACH OTHER, not to mention the 1157cc CB1100F/CB1100R DOHC-4 & 999cc Japauto CR750 & Honda Britain replicas. Not to mention all of the NON-HONDA so-called “competition” – Which is actually kicking butt on the Honda series these days. What with Suzuki motors having the same bolt plan & cylinder spacing such that they can mix their ’70s-’80s engine compoents with their ’90s & Y2K+ series, rendering unbeatable KATANA engines for Moto-Martin framed specials. Which is to say we’ll NEED these alternative models if we in the HONDA camp, under the Honda banner, are to have any hope of winning.

It wouldn’t just breath some life back into Honda classic racing. The racing ‘WING would blow some people’s minds!

Seriously though, if you’re turning the very capable GL1200 chassis into a raked-out ’70s FASHION VICTIM titty-magazine centerfold? I’m out. Well … to tell the truth? I’m probably gonna check back into this thread/blog every now & again for shitz & gigglz, but it ain’t gonna pique my INTEREST per se.

Thanks so much for the feedback and information!!! It’s lot to digest! As far as raking the front end it is very minimal. The only reason I did it at all was to keep the front end in line with the back end. It would have looked wrong if I left it at stock height. I don’t like choppers at all. Never have, never will. I’ve got some reading to do! Thanks again for the reply!